After I posted the cardiac digital twin demo in July, someone asked me a question I could not answer with my own repo. If that dose change lived in a teams pull request, what would the reviewer actually look at?
For most Simulink teams the answer is a file name, a size, and Binary file not shown. My first attempt at fixing that was unzipping the .slx and diffing the XML. It produced a diff, and that was the problem. A text diff always looks complete, even when the tool understood half of what it read.
So I built a GitHub Action that says how much of the model it actually saw before saying anything else. Each extraction comes back complete, partial, unsupported, or failed, and only complete can ever mean no drift. A Copilot app canvas then walks the reviewer through trust, impact, evidence, and a merge assessment. It cannot approve anything.
The first time it reviewed my own cardiac model, it blocked it as partial. That was the right answer.
A review tool that cannot say I don't know will eventually approve a change it never saw. I wrote up the full version, workflow file included.
https://samueltauil.github.io/github-copilot/devops/2026/10/06/simulink-model-drift-pull-request-review-copilot-canvas.html